Sadia Rahman Jhilik / Physics / Faculty Mentor: Muhammad Huda
Silicon carbide (SiC) is a wide band gap semiconductor that demonstrates physical properties like high critical field strength, thermal conductivity, and electron saturation velocities. According to the stacking pattern of the Si-C bilayers, SiC has over 200 polymorphs, where 2H-, 4H-, 6H-, and 8H-SiC are the most common hexagonal polymorphs. Non-stoichiometric SiC materials, especially silicon-rich SiC, are tailored to reduce SiC’s high bandgap and enhance solar light absorption efficiency. First-principles density functional theory (DFT) calculations have demonstrated that silicon-rich silicon carbide (SiC) nanoclusters exhibit structural stability and possess tunable energy gaps. To explore the potential of non-stoichiometric SiC in the bulk phase, we investigated silicon-rich SiC by substituting carbon atoms with silicon in different configurations within silicon carbide bulk. We have reduced the band gap to below 1.5 eV by substituting silicon atoms into various hexagonal silicon carbide (SiC) phases. The procedure aligns with the optimal range for efficient solar energy conversion. Notably, the defect bands introduced by these substitutions are primarily influenced by the p-orbital contributions of the doped silicon atoms.
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